1) Field of the Invention
The field of this invention relates to dissolution testing equipment for determining the dissolving rate of drugs encapsulated in the form of a tablet, capsule or caplet, which are commonly known as pills and more particularly to an interfacing piece of equipment to be used as a dissolution sampling apparatus.
2) Description of the Prior Art
Drugs are commonly manufactured in the form of pills. The reason for using pills is that when the drug is swallowed by a human, the drug will be disseminated by the body over a period of time as the pill dissolves. Manufacturers of pills are required by law to determine the precise dissolving characteristics of their pill before it is placed on the market. In order to determine the dissolving characteristics, dissolution test equipment is utilized. Although dissolution test equipment is commonly used in conjunction with drugs designed for human consumption, it is considered to be within the scope of this invention to use it with other animals such as horses, cows, rabbits, cats, dogs, monkeys and so forth.
Every form of dissolution test equipment generally utilizes a plurality of liquid containing flasks called testing vessels. In each flask is to be placed a liquid called media, with this media essentially duplicating the liquid solution that is contained within the stomach of the human body. The precise quantity of the solution is placed within the flask. The pill is then inserted into the flask and the time of the insertion then noted. A mixing paddle is inserted within the flask with mixing at a precise rate then occurring. The mixing procedure is to duplicate the natural turbulence that is created within the stomach of the human. Aliquots are removed from the solution at precise time intervals with these aliquots then being analyzed to determine the amount of drug that has been dissolved within the solution in relation to the time that the pill has been in the solution.
In order to insure that the testing process is accomplished as accurate and quickly as possible, such dissolution testing apparatus, in the past, has been designed as follows:
1. Normally the dissolution testing apparatus would have six or eight flasks. Dissolution testing of the pill is accomplished simultaneously in all six or eight flasks with each flask to receive a pill. The average dissolving rate is then calculated between the flasks.
2. The flasks are placed in a bath with this bath to be maintained at a precise temperature. The temperature level is to essentially duplicate the temperature of the stomach liquid within the human.
In the past, the procedure in conjunction with the six or eight flasks is for the technician to remove the media from each individual flask and place it within a collecting vessel. A precise quantity of the media is to be removed and placed within the vessel. At times, it is then required to replace that precise same quantity of raw media back into the flask from which the media has been removed. Also, at other times the media that is being tested is to be reinserted back into the flask. Previously, this tedious procedure of removal of aliquots and replacement of the aliquots or media back into the flask has all been accomplished manually. Inherently, inaccuracies develop. Also because of the time it takes to complete the manual removal procedure, additional inaccuracies develop because what is being calculated is the amount of dissolution of drug within the media within a certain period of time and the removal and replacement procedure takes. time which affects the accuracy of the readings.
The dissolution sampling apparatus of the present invention is designed to automatically extract samples (aliquots) from multiple flasks that contain media and deposit these aliquots within collecting vials with each aliquot being deposited in a separate collecting vial. The sampling apparatus of this invention can also resupply the aliquot that has been removed back to the flask from which the sample has been taken or the sample can actually be discarded as waste. When discarded as waste, an additional quantity of the raw media liquid can be resupplied to the flask from which the sample has been taken. The present invention is to be used in conjunction with a dissolution test apparatus such is as shown and described within U.S. Pat. No. 5,639,974 which issued on Jun. 17, 1997. However, the present invention can be effectively interfaced with numerous other types of dissolution test apparatus and it is not intended to be solely used with the dissolution test apparatus of the aforementioned patent. However, all dissolution test apparatuses use a multitude, usually six to eight in number, of flasks with the media that is to be removed from each of these flasks. Within each flask is deposited a pill and the flask will normally include a mixing device which is to be used to create a turbulent action within each flask essentially duplicating the. turbulent action that is naturally created within the human stomach. The definition of pill is to also include capsules and caplets or any type of device which is to dissolve.
The present invention can comprise two different models with both models utilizing a plurality of piston operating devices which we refer to as syringes. There is to be a syringe for each vessel that contains media. Each syringe includes a body that is basically hollow within which is mounted a piston. This piston is retractable and expandable within the body. This retraction and expansion is accomplished by means of a motor which is precisely controlled by software. Associated with each syringe are a plurality of valves. Each valve is also operated by the software as to whether the valve is opened or closed. The first model is referred to as the DISSOSCAN and the-second model is referred to as the MAXIMIZER. The DISSOSCAN utilizes a single three-way solenoid valve that are mounted in conjunction with each syringe. The MAXIMIZER utilizes four two-way solenoid valves operated to accomplish the valving in conjunction with each syringe. The MAXIMIZER model is designed to be more versatile than the DISSOSCAN model with the MAXIMIZER able to perform a greater number of functions. However, the MAXIMIZER model has a disadvantage in that it is inherently more expensive.